Ah yes potentially getting us one step closer to immortality, hardly worth killing an animal!
I mostly eat vegan because I do have a strong dislike of factory farming and the way animals are treated there. But killing animals is a fact of life and I think scientific progress is a very valid reason to do so.
To put it in perspective, a lot of shark young will kill each other in the womb such that only the strongest is birthed. These animals eat other animals alive, etc.. etc.. My point being it is not like the option is between a rosy utopia or human-inflicted suffering.
I'm not against scientific research per se or living a bit more but... is immortality (or living for, say, 200 years or more) really something we should strive for?
Many aspects of human society assume, one way or another, that our life expectancy is fairly limited. From politics (even absolute monarchs or dictators eventually die), to economics (think about retirement, for example), demographics (if everyone is immortal and everyone keeps having children, what happens?), even psychology ("everything passes").
Are we willing to throw these implications away? What would be the purpose?